Safety hook



L. P. KELLEY Feb. 10, 1959 SAFETY HOOK Filed Jan. 10, 1955 2 Sheets-Sheet l INVENTOR. LEO/V B 1721454 Feb. 10, 1959 p, KELLEY 2,872,717

I SAFETY HOOK Filed Jan. 10, 1955 2 Sheets-Sheet 2 mmvrm Zia/v B 15:44 59 United States Pat SAFETY HOOK Leon P. Kelley, Long Beach Calif.

Application January 10, 1955, Serial No. 480,805

2 Claims. (Cl. 24-232) This invention relates generally to lifting apparatus and is concerned more particularly with an improved lifting hook device employed in connection with the lifting cable of a hoist, crane, or other similar apparatus. A general object of this invention is to provide a simple, practical and efficient lifting hook of improved construction which is designed to positively retain a lifting cable therein so as to avoid accidental displacement of the cable therefrom and possible dropping of the object being lifted or lowered.

Lifting hooks are commonly employed at the lower ends of the lifting cables of hoists, cranes, etc., the hooks frequently being carried by tackle-blocks at the lower bight of the hoisting cables. Such hooks are ordinarily large and cumbersome and thus are not easily handled when connecting or disconnecting the object to be hoisted or lowered.

Conventional lifting hooks currently in use are massive steel forgings, usually of T-shapecl cross section to pro vide the strength necessary to lift heavy objects. Such hooks have an upper re-entrant opening through which the lifting cable is inserted into and removed from the hook. During the operation of lifting or lowering a heavy object, the suspended cable may swing laterally and the object may strike with suddenness against an abutment, as for example when the object is lowered too abruptly upon a floor or strikes a Wall. When this situation occurs, sudden slackness in the object supporting cable may cause the upper loop end of the cable to snap upwardly in the open hook with the result that the loop may become displaced through the opening of the hook to release the object supported by the cable. While this deficiency of conventional lifting hooks has long been recognized, no satisfactory solution to the problem has been proposed, even though safety latches or catches for closing hooks or loops are well known in various fields. The main reason for failure to embody such safety latches of lifting hooks is that the hooks, by .reason of their peculiar shape and onepiece forged construction, do not lend themselves to the modification which is necessary to movably mount the latches thereon, such modification of the hook requiring drilling or other machining which might weaken the structure.

It is, therefore, another object of this invention to provide a safety-type lifting hook which is as strong, or stronger, than conventional forged steel hooks and yet of lighter weight to make for greater ease in handling.

According to the invention, this object is attained by providing a hook of laminated construction, the laminahook, of the character referred to, which includes a retainer means normally operative to close the re-entrant opening of the hook so as to prevent accidental release of the lifting cable from the hook and thus guard against dropping of an object being handled by the hoist or crane.

Another object of the invention is to provide a lifting hook of the class specified in which the laminations are so formed as to provide a recess or slit therebetween in which the retainer means is mounted for movement to a first position to open the hook for receiving the lifting cable and to a second position to bridge the re-entrant opening so as to retain the cable loop within the hook.

Another object of the invention is to provide a lifting hook of the type indicated in which the retainer means consists of a closure latch disposed within the recess and pivotally mounted for movement to hook-opening and closing positions. A related object is to provide a closure latch which normally is actuated under the influence of gravity to a hook-closing position, said latch having a weighted end for effecting this result. By this provision, the latch is adapted to pivot to an open position, within the hook portion, upon forcing the loop end of the cable into the hook and to thereafter pivot automatically to the hook-closing position to retain the loop within the hook.

A further object of the invention is to provide a hook structure of the character indicated in which the gravityactuated latch is located entirely within the confines of the hook body so as to protect the latch'against striking objects which might release the latchfrom its operative position. A related object is to provide a hook structure in which the weighted end of the pivoted latch has a finger-piece or stud by which the latch may bemanipulated to its open positiomsaid stud projecting outwardly through an arcuate opening in a side of the hook body and-being protected against damage by means of an arcuate web or rib projecting from the hook body, alongside said arcuate opening.

A still further object of the'invention is to provide a hook structure in which the laminated hook body may be formed with either one or two hook portions, each provided with a gravity-actuated closure latch and associated parts, such a double book being desirable in cases where more than one cable is used as a sling for a heavy object being handled by the hoist or crane.

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred forms and applications of my invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a perspective view of one form of the improved lifting hook. Fig. 2 is a side elevation of the lifting hook shown in Fig. 1. Fig. 3 is a vertical sectional view through the hook, taken as indicated by line 3-3 of Fig. 2. Fig. 4 is a perspective view of the gravityactuated closure latch. Fig. 5 is a side elevational view of another form of the lifting hook. Fig. 6 is a plan view of the hook device shown in Fig. 5. Fig. 7 is a vertical sectional view through the hook, taken as indicated by line 7-7 of Fig. 5. Fig. 8 is a perspective-view of one of the closure latches employed in the hook device illustrated in Fig. 5.

The present invention, as exemplified in Figs. 1 m4 of the drawings, comprises, generally, a hook body A having an integral cable-receiving hook portion B, a. cable-retainer means C in the form of a gravity-actuated, pivoted latch element, and manually operable means D for pivoting the latch element to its inoperative position.

The body A is of laminated construction being composed of a pair of side plates 10 and 11 between which are disposed upper and lower filler pieces 12 and 13. Each side plate consists of an inclined shank or stem portion 14, the lower end ofw hich curves laterally apd 3 upwardly to provide the hook portion B. As shown, the upper extremity or tip 15 of the hook portion terminates at a predetermined distance from the stem portion 14 to define therebetween a re-entrant opening 16 through which a cable may be passed into the hook portion B in the manner and for the purpose to be hereinafter explained. I

The filler piece 12 may be in the form of a generally circular disc which is secured in place between the upper ends of the shank portions 14 of the side plates and 11 by plug welds 18 which permanently join these parts together to provide a strong, rigid structure. The lower filler piece 13is of generally U-shape and conforms to the contour of the hook portion B between the side plates of which it is permanently secured by plug welds 19. As shown in Fig. 3, the filler pieces 12 and 13 are also seam-welded to the side plates 10 and 11, as indicated at 20. As also shown in this view, the edges of the side plates 10 and 11 which define the inner arcuate edge of the hook portion B are preferably rounded as indicated at 21, so as to avoid sharp corners which might injure the lifting cable. In practice, the filler piece 13 terminates short of the tip 15 in which case the portions of the side plates 10 and 11 forming the tip are drawn together and welded closed at 15.

The lower edge of the tiller piece 12, the upper edge of the filler piece 13 and the inner surfaces of the side plates 10 and 11 together define a narrow opening or slit 25 within the stem or shank 14. The side plates 10 and 11 have aligned holes 26 and 27 respectively at the slit portion of the shank, the hole 26 being smaller than the plate v10 to extend alongside the slot 41 and concentric therewith, the rib projecting from the plate slightly beyond the outer end of the operating stud 40, as shown in Fig. 2.

The side plates 10 and 11 and the upper filler piece 12 are provided with aligned holes which provide an eye 45 by wihch the safety hook may be suspended from the lifting cable 46 or from the tackle block of a hoist or crane.

To apply the improved safety hookto use, it is suspended from the wind-up cable 46 of a hoist or crane by looping the cablethroug'h the eye 45 as shown in Fig. l. When it is desired to lift a heavy object, a lifting cable 47 is suitably attached to the object and a loop or bight 48 of this cable is placed in the hook portion B as also illustrated in Fig. 1.

To so connect the cable 47 to the hook, its loop 48 is directed through the re-entrant opening or slot 16 and lowered into the hook. As the loop 48 is thus inserted, it engages the pawl-like end 36 of the latch element 35 to pivot the latter to the inoperative position indicated by broken lines in Fig. 2, against the action of the weighted end 37, with the operating stud 40 riding upwardly in the hole 27 and being screw-threaded. Extending through these holds and transversely across the slit 25 in a pivot bolt 28 having a head 29 abutting the outer surface of the plate 11 and a reduced, threaded end 30 screwed through the hole 26. A check nut 31 is screwed onto the projecting threaded 'end 30 of the bolt 28 and set up against the outer surface of the plate 10 to prevent loosening of the bolt.

The cable retainer means C consists of a closure latch element 35 of the form illustrated in Fig. 4. This element is of a thickness slightly less than the width of the slit 25 and has a relatively pointed, pawl-like end 36 and an opposite, relatively wide end 37. Substantially midway between its ends, the latch element 35 has a hole 38 by which it is pivotally mounted on the bolt 28, within the slit 25. When so installed in the slit, the relatively pointed end 36 of the latch element projects from the shank and across the re-entrant opening 16 with its tip 39 engaging under the tip 15 of the hook as shown by full lines in Fig. 2. The latch element 35 is normally maintained in this operative position to close the hook under the influence of gravity, it being noted that the larger, heavier end 37 of the element provides a weight which overbalances the end 36.

It is necessary that the latch element 35 be pivoted manually to the inoperative position indicated by broken lines in Fig. 2, in order to withdraw its end 36 from across the opening 16 so as to permit withdrawal of the cable from the hook. To facilitate such pivotal movement of the latch element, I make use of the manuallyoperable mean D. This means consists simply of a pin or stud 40 screwed into a threaded hole in the weight end 37, said stud projecting outwardly through an arcuate slot 41 provided in the side plate 10 and arranged concentrically of the axis of the pivot bolt 23.

When the latch element 35 is in its operative or closed position, the operating stud 40 is located at the lower end of the arcuate slot 41. To effect pivotal movement of the latch element 35 to its inoperative, open position it is only necessary to slide the stud 40 upwardly in the arcuate slot 41 to overcome the force of gravity. In order to protect the projecting end of the fingerpiece or stud 40 against damage, I provide an arcuate web or rib 44 which is welded against the outer side of the arcuate slot 41. When the cable loop 48 clears the end 36 of the latch element 35, the latter is released, whereupon the weighted end 37 functions to return the element to the operative position in which its latching end 36 extends across the opening 16 with its tip 39 engaging the underside of the tip 15 of the hook. During this movement, the-operating stud or trigger 40 moves downwardly in the arcuate slot 417 Prior to lifting the object, slackness may occur in the cable 47 and this may tend to cause upward movement ing the lifting or lowering of the heavy object, due to uneven pulling force exerted by the hoisting mechanism or to paying out of the cable 46 at an excessive rate. This condition may also occur if the object being lifted or lowered inadvertently strikes against a stationary surface. Such accidental release of the cable loop 48 from the hook will obviously allow the object to drop and this may cause damage to the object and injury to workmen.

On the other hand, the present safety hook obviates such a condition 'by locking the cable loop Within the hook to prevent its displacement therefrom. Should the cable loop 48 move upwardly in the hook, it will be prevented from escaping through the opening 16 by the latch element 35 whose end 36 extends across the opening and engages underthe tip 15 of the hook portion B. Thus, by my invention accidental release of the lifting cable from the hook is positively prevented and maximum safety is assured.

After the object has been placed in the desired location, the cable 47 may be disconnected from the hook. T 0 effect this result, the operating stud 40 is simply moved upwardly in the curved slot 41 so as to pivot the latch element 35 in a direction to displace its end 36 from across the opening 16 of the hook, as shown by the broken lines in Fig. 2. With the hook thus opened, the cable 47 may be detached from the hook by drawing its loop 48 outwardly through the opening 16.

As a particular feature of improvement, the present safety hook is of laminated construction. By this provision, the hook may be fabricated from plate stock possessing maximum strength so that a hook of smaller proportions may be'made to handle the same loads as a larger, more cumbersome hook of forged steel construction.

Referring now to Figs. 5 to 8 of the drawings, it is within the present concept to provide an alternative hook structure in which the hook body A has a pair of laterally spaced hook portions B, each adapted to lift a cable forming part of a sling or other means attached to an object to be lifted. In this embodiment of the invention, the body A includes substantially triangular side plates 50 and 51 between which are welded upper and lower filler pieces 52 and 53, the lower pieces cooperating with the side plates to provide the hook portions B. At the upper end of the structure is a hole or eye 54 by which the hook device may be suspended from the cable of a hoist.

Pivoted on transverse bolts 55, within a slot or opening 57 defined by the filler pieces and side plates, are latch elements 60 of the type illustrated in Fig. 8, providing the cable retainer means C. Each element 60 has a pawl-like latching end 61 and a larger weighted end 62 which normally functions to pivot the element in 'a direction to maintain its end 61 in position to close the re-entrant opening 64 of the hook portion. Each latch element 60 has an operating means D which consists of an operating stud 65 at its weighted end 62, each stud projecting outwardly through an arcuate opening 66 formed in the side plate 50. Guard ribs 67 welded to the side plate 50 protect the operating studs 65 against damage The device shown in Figs. 5 to 8 of the drawings, is similar to that disclosed in Figs. 1 to 4 but is provided with a pair of hooks to adapt it for use in situations where more than one lifting cable is employed for lifting extra heavy and bulky objects. For example, in building construction work, it is frequently necessary to lift precast concrete panels or slabs weighing approximately twenty tons and which are of substantial width. In such case, steel lifting cables are attached to a pair of eye-bolts projecting from the concrete slab. By employing the double hook device of Figs. 5 to 8, each lifting cable may be attached to one of the hooks B to distribute the load and to effect better lifting control.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A lifting hook device, including, a body having a substantially upright shank, the lower end of the shank being arcuate and providing a hook portion, the tip end of the hook portion being spaced from said shank and defining therewith a re-entrant opening through which a cable may be inserted into and removed from the hook portion, said shank having a recess therein opening into said i e-entrant opening, and retainer means carried within said recess and consisting of a latch element pivoted Within said recess and projecting into the re-entrant opening for movement to a first position to engage beneath said tip end so as to close said opening and retain the cable in said hook portion, and to a second retracted position to allow insertion into and removal of the cable from the hook portion through said opening, and manually operable means for pivoting said latch element to said retracted position, said manually operable means consisting of a stud on said latch element projecting laterally outwardly through an arcuate slot in the shank arranged concentrically of the pivot of said element, and guard means on said body for protecting said projecting stud.

2. A lifting hook device, including, a body having a substantially upright shank, the lower end of the shank being arcuate and providing a hook portion, the tip end of the hook portion being spaced from said shank and defining therewith a re-entrant opening through which a cable may be inserted into and removed from the hook portion, said shank having a recess therein opening into said re-entrant opening, and retainer means carried within said recess and consisting of a latch element pivoted within said recess and projecting into the re-entrant openingfor movement to a first position to engage beneath said tip end so as to close said opening and retain the cable in said hook portion, and to a second retracted position to allow insertion into and removal of the cable from the hook portion through said opening, and manually operable means for pivoting said latch element to said retracted position, said manually operable means consisting'of a stud on said latch element projecting laterally outwardly through an arcuate slot in the shank arranged concentrically of the pivot of said element, and guard means on said body for protecting said projecting stud, said guard means consisting of an arcuate rib projecting from said body and arranged concentrically of said arcuate slot.

References Cited in the file of this patent UNITED STATES PATENTS 231,381 Vare Aug. 17, 1880 544,483 Eckert Aug. 13, 1895 716,515 Bonner Dec. 23, 1902 821,286 Saunders May 11, 1909 1,152,064 Washington et a1 Aug. 31, 1915 2,404,602 Stolflet July 23, 1946 

